PDF malware analysis — malicious · 4df79e44a1a8deb4

MALICIOUS

PDF

27.7 KB Created: 2011-05-26 16:38:46 +03:00 Authoring application: bing.wiki.usfca.edu (via mPDF 5.0)

MD5: 9db3a23b68472829d0d934794dff2de6 SHA-1: aca21fa7ed1e42c6d7224dfcff0311c3adbcac0d SHA-256: 4df79e44a1a8deb49fb2e99bb2ee4a93e64c7c9e7ee55ddad854cd384e21684f

106 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF file exhibits high-confidence indicators of maliciousness, including ML classification and the presence of JavaScript. The embedded JavaScript stream, identified as 'javascript_obj0022_000.js', is obfuscated and likely serves to download and execute a second-stage payload. The 'unescape()' call further suggests an attempt to hide malicious code. Due to the obfuscation, the exact payload and delivery mechanism cannot be definitively determined.

Machine Learning

Nyx PDF Classifier malicious score 0.9994

Heuristics 4

unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
JavaScript action low PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
Embedded JS stream low PDF_JS

PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0022_000.js` `10e15f9e8e631690248396d575e9652903435250e89141f7cc58e4b3e9b10d1b`	pdf-javascript-stream	PDF /JS object 22 at offset 0x6709	136 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long hex-escaped blob(s).
`stream_003_off00001194.bin` `ded1520fd68b91798ef4502ba393be29e6762be445da6319489229b957e57958`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x1194	17756 bytes
`font_01_sfnt_off00003fa6.bin` `a8ed3909966b10c026f46212f55dce68c94667ce1ac039797d3ebfa1d644dacf`	pdf-font-stream	PDF embedded font (sfnt) at offset 0x3FA6	17892 bytes

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